This report describes the morphologic features of 73 hearts examined at necropsy with aortic valve atresia. The patients ranged in age from 1 to 17 days (avergage 5) and 75 percent were boys. Previous reports on aortic valve atresia described only the occurrence of a hypoplastic left ventricle with or without atretic mitral valves. In the present study of 73 cases 4 were found to have normal or near-normal sized left ventricles rather than hypoplastic ones and 3 of them had normally developed mitral valves.